New contract: monitoring of the construction worksite of line 18 of the Grand Paris Express

Sixense would like to thank the consortium in charge of the works for their trust on this new project of the Grand Paris Express. The forecast duration of this new contract for monitoring of the works and nearby infrastructures is of 5 years. Line 18 will be about 35 km-long from the Orly Airport railway station to the Versailles-Chantiers railway station.


The market, notified on May 14th of 2020 to the association of several entities of @Vinci Construction and @Spie batignolles, includes the realisation of :


  • a bored tunnel of about 11 800 ml, of 7,8 m of effective diameter excluding crossing of structures,
  • trenches (cut and covered) of about 850 m between the tunnel and the aerial section comprising the temporary reorganisation of the Croix de Villebois road crossing intercepted by the works,
  • structural works of the underground railway stations of Antonypole, Massy-Opéra and Massy-Palaiseau,
  • thirteen annexed works, including the connecting branches of the tunnel.


Sixense Monitoring was assigned the auscultations to be carried out in the framwork of the project related to the drilling of the tunnel and to the construction of the infrastructures (excluding Launching shaft and Cut & Cover and excluding inside topography of the railway stations and right-of-ways).


This sector comprises 2 very sensitive areas which will need to be carefully monitored : the important railways nearby the future Massy-Palaiseau railway station and the Orly Airport area.


A permanent Sixense team will remain on the field at the base of the worksite in order to stay as close as possible to the work teams to carry out the mission that we have been assigned to. The team will implement a diversity of auscultation measures, including:


  1. Automated topographic monitoring with our now well-known Cyclops and Centaurs which will examine the nearby infrastructures of the project,
  2. Measures by inclinometers of the vertical structures of the infrastructures under construction,
  3. Stresses and constraints monitoring of the infrastructures under construction or the instrumented voussoirs,
  4. The geotechnical monitoring of the 16 sections of reinforced measures of the 2 tunnels comprising inclinometers in the field, multipoints extensometers in boreholes and interstitial pressure cells.


Geoscope will be the management support tool for all companies to access all auscultations of the project. This tool had been designed with a multi-actors approach allowing all different parties of the same project to have access to all the useful data : intuitive visualisation of the data, management of the alarms for level exceedances, visualisation of the construction site progression and access to all reports of auscultations.


This project is once again an opportunity for us to implement our monitoring expertise of urban works build up throughout the years with tunnel projects in urban areas where we have been able to step in.